PointArray are crucial in J2D-renderer implementation. They make abstraction of the underlying data storage (float[], JTS coordinate sequence, disk storage, compressed data, etc.). The whole J2D-renderer geometric objects are build on top of them. The org.geotools.renderer.array package need to be ported as an org.geotools.geometry.array package and PointArray2D must implements org.opengis.spatialschema.geometry.geometry.PointArray.